Specific Aims and Hypothesis: The purpose of this study is to identify if the administration of NKP 608 decreases sputum production and improves the clinical symptoms of chronic bronchitis. The primary experimental objective is to compare the effects of placebo and four daily doses (0.1mg, 1mg, 5mg, 20mg) of NKP 608 upon the amount of sputum that can be induced by hypertonic saline. The secondary experimental objectives are to evaluate the effect of NKP 608 on: health related quality of life and clinical signs and symptoms of chronic bronchitis, the safety and tolerability compared to placebo, and population pharmacokinetics in a sample trial population. This study will employ a multiple-center, randomized, double-blind, placebo-controlled, parallel group design. Patients will make 6 visits to the investigation site. Subjects must have been taking all allowed concomitant medications without change for at least 2 weeks prior to screening. Subjects with chronic bronchitis that have a forced expiratory flow rate (FEV1) is greater than or equal to 35% of predicted and whom have no other unstable disease will be screened for inclusion in the study. Approximately 10-20 ml of blood will be drawn at each visit. Each subject will also undergo a physical exam. The ECG will be repeated on Visit 4 and Visit 6. Lung function will be evaluated by spirometry. Bronchodilator medications will be withheld for a minimum of 6 hrs. prior to testing. Daily diaries will be completed. The study has been closed by the sponsor. 15 subjects were screened, 10 enrolled and 8 completed the study at the site. Data is being compiled by the sponsor and results are not available.